On 06/05/2012 10:50 PM, Ben Collins wrote:
> The commit introducing pcibios_io_space_offset() was ignoring 32-bit to
> 64-bit sign extention, which is the case on ppc32 with 64-bit resource
> addresses. This only seems to have shown up while running under QEMU for
> e500mc target. It may or may be suboptimal that QEMU has an IO base
> address > 32-bits for the e500-pci implementation, but 1) it's still a
> regression and 2) it's more correct to handle things this way.
Where do you see addresses over 32 bits in QEMU's e500-pci, at least
with current mainline QEMU and the mpc8544ds model?
I/O space should be at 0xe1000000.
I'm also not sure what this has to do with the virtual address returned
by ioremap().
> Signed-off-by: Ben Collins <bcoll...@ubuntu.com>
> Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
> ---
> arch/powerpc/kernel/pci-common.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/kernel/pci-common.c
> b/arch/powerpc/kernel/pci-common.c
> index 8e78e93..be9ced7 100644
> --- a/arch/powerpc/kernel/pci-common.c
> +++ b/arch/powerpc/kernel/pci-common.c
> @@ -1477,9 +1477,15 @@ int pcibios_enable_device(struct pci_dev *dev, int
> mask)
> return pci_enable_resources(dev, mask);
> }
>
> +/* Before assuming too much here, take care to realize that we need sign
> + * extension from 32-bit pointers to 64-bit resource addresses to work.
> + */
> resource_size_t pcibios_io_space_offset(struct pci_controller *hose)
> {
> - return (unsigned long) hose->io_base_virt - _IO_BASE;
> + long vbase = (long)hose->io_base_virt;
> + long io_base = _IO_BASE;
> +
> + return (resource_size_t)(vbase - io_base);
Why do we want sign extension here?
If we do want it, there are a lot of other places in this file where the
same calculation is done.
-Scott
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
